This invention relates generally to a power tool accessory and, more specifically to a work piece stop for use with wood working machines.
Devices used to stop a work piece at a specific positioning limit are well known. They are used extensively in wood working and also in the working of metals and other materials. The basic advantage of working to a stop is that one or more pieces can be very accurately positioned for cutting, bending, or other processing operations. Cutting several pieces which are all positioned to a stop produces a repeatable precision that would be most difficult to accomplish by layout, and cutting to a mark, if it could be duplicated at all.
Cutting to a stop is commonly done in production operations because of the precision and economy of repetitive cutting or forming operations, and many machines are equipped with adjustable or fixed stop devices. Such production stop devices generally are designed for specific production operations.
Cabinet makers, on the other hand, commonly clamp a block of wood (a stop block) onto a bench or other work base, such as a miter box, to assure that the work piece will be properly positioned. There are, however, inherent problems in clamping a stop block in place. For example: figuring out where to clamp the block takes time and may require cutting a special block, or looking for a suitable scrap to be used for the purpose; a clamp must be located that will be big enough to reach over the stop block and the fence or table or other base or guide that the stop block is to be clamped to; if the block is not positioned with care variations in the angle of the stop block may introduce errors in the position of the cut; if the stop block is not positioned away from certain adjacent surfaces a pocket may be created where sawdust or chips from the material being cut will build up and cause an error of increasing magnitude in successive work pieces; when pieces of a like nature are being made, but having a cut performed to a varying distance after a small number of pieces are processed, the adjustment of the stop block may be inordinately time consuming; and when pieces are being positioned on a radial arm saw or other similar machines, the clamp that holds the stop block may get in the way of the moving parts of the machine such as the saw handle or motor.
In an effort to overcome the above disadvantages, and others, a number of stop mechanisms have been developed for certain particular machines. However, such devices have for the most part been very limited in there application and have been relatively expensive. Examples of prior stop mechanisms are disclosed in U.S. Pat. Nos. 3,124,181 and 4,256,000.
The object of this invention, therefore, is to provide an improved, more versatile stop mechanism for use with a variety of power tools.